Background Transgender women sex workers (TGW-SW) are disproportionally affected by HIV and have reduced access to testing. Moreover, information regarding their behaviours and health needs is scarce.

Methods A behavioural survey and a targeted testing programme in prostitution sites were conducted in Milan and Monza areas. The non-profit organisation ‘ALA Milano Onlus’ and ‘San Gerardo’ Hospital (Monza) implemented a mobile HIV testing unit involving a TGW peer educator, four physicians, a counsellor, a psychologist and a cultural mediator. All TGW-SW were offered anonymous HIV and hepatitis C virus (HCV) oral testing and asked to fill a questionnaire on sexual habits, drug abuse, and knowledge and attitudes towards HIV and STDs.

Results Between May and July 2017, 130 TGW-SW, predominantly migrants, were contacted during 15 street visits; among them, 78 (60%) were interviewed. HIV and HCV testing were accepted by 53 (42%) and 67 (52%) TGW-SW, respectively. Twenty-five (19.8%) subjects who reported already established HIV infection were not retested. Seven patients received a new diagnosis of HIV, while nobody tested positive for HCV. Overall, HIV prevalence was 13.2% (25% including those with already known HIV infection). Recent arrival in Italy and young age were associated with risk of undiagnosed HIV infection. Inconsistent condom use was commonly reported during commercial sex (27%) and with non-commercial partners (64%). Alcohol and cocaine abuse were common problems which facilitated risky behaviours.

Conclusions Oral rapid HIV and HCV testing for TGW-SW in outreach settings were feasible and acceptable and led to a considerable number of new diagnoses. Interventions tailored to TGW-SW, focused on HIV prevention, testing and engagement in care, are fundamental.